1. Field of the Invention
This invention relates to an apparatus designed to mix various substances, normally liquids, and more particularly to a cooling bladder assembly for cooling the mixing chamber vessel.
2. Description of the Prior Art
A sandmill is a type of apparatus used for stirring and mixing various substances, for example, paints, clay/water mixtures, and the like, in which particulate material such as glass beads or shot is added to the liquid or slurry for breaking up and dispersing the components to be mixed. The shot or beads are then filtered out of the mixture for re-use, leaving the mixed substance.
Such an operation generates substantial amounts of heat in the mixing chamber, the heat generated being deleterious both to the chamber assembly and to the mixture inside the chamber. Thus, most mills of this type have an integral cooling jacket surrounding the actual mixing chamber, through which water or other coolant is circulated. The jacket is permanently fixed to the mixing chamber and extends circumferentially around the chamber, normally encompassing the entire height of the chamber. This type of arrangement permits cooling of the inner chamber but affords no fine control of the cooling operation due to the continuity of the cooling jacket. Such fine control is desirable because the upper portions of the sandmill are normally hotter than the lower portions.
In addition, should repairs to the mixing chamber or cooling jacket become necessary, the entire apparatus must be disassembled for repairs or replacement. The operation is generally difficult because of the integral nature of the mixing chamber and jacket. This arrangement also risks contamination of the solution being mixed should a crack occur in the wall of the mixing chamber during operation. Similarly, faults in the water jacket which can not be repaired, require the replacement of the entire chamber/jacket assembly.